What are the new coordinates of X if X was rotated 180 degree ? (the center of rotation is the origin)

Acircle has a diameter will endpoints of (-2,8) and (6, 4). what is the center of the circle

Tom had a total of $220 and he spent $35 on a basketball ticket . what percent of his money did he have left?

If the speed of an electromagnetic wave is 100,000 cm/s and its wavelength is 100 cm, what is its frequency? a) 100,000 cycles per second (hz) b) 1 × 10-3 cycles per second (hz) c) 10,000,000 cycles per second (hz) d) 1,000 cycles per second (hz)